drivers/cpufreq/omap-cpufreq.c

   1 /*
   2  *  CPU frequency scaling for OMAP
   3  *
   4  *  Copyright (C) 2005 Nokia Corporation
   5  *  Written by Tony Lindgren <tony@atomide.com>
   6  *
   7  *  Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
   8  *
   9  * Copyright (C) 2007-2011 Texas Instruments, Inc.
  10  * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License version 2 as
  14  * published by the Free Software Foundation.
  15  */
  16 #include <linux/types.h>
  17 #include <linux/kernel.h>
  18 #include <linux/sched.h>
  19 #include <linux/cpufreq.h>
  20 #include <linux/delay.h>
  21 #include <linux/init.h>
  22 #include <linux/err.h>
  23 #include <linux/clk.h>
  24 #include <linux/io.h>
  25 #include <linux/opp.h>
  26 #include <linux/cpu.h>
  27
  28 #include <asm/system.h>
  29 #include <asm/smp_plat.h>
  30 #include <asm/cpu.h>
  31
  32 #include <plat/clock.h>
  33 #include <plat/omap-pm.h>
  34 #include <plat/common.h>
  35
  36 #include <mach/hardware.h>
  37
  38 #define VERY_HI_RATE    900000000
  39
  40 #ifdef CONFIG_SMP
  41 struct lpj_info {
  42         unsigned long   ref;
  43         unsigned int    freq;
  44 };
  45
  46 static DEFINE_PER_CPU(struct lpj_info, lpj_ref);
  47 static struct lpj_info global_lpj_ref;
  48 #endif
  49
  50 static struct cpufreq_frequency_table *freq_table;
  51 static struct clk *mpu_clk;
  52
  53 static int omap_verify_speed(struct cpufreq_policy *policy)
  54 {
  55         if (freq_table)
  56                 return cpufreq_frequency_table_verify(policy, freq_table);
  57
  58         if (policy->cpu)
  59                 return -EINVAL;
  60
  61         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
  62                                      policy->cpuinfo.max_freq);
  63
  64         policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000;
  65         policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000;
  66         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
  67                                      policy->cpuinfo.max_freq);
  68         return 0;
  69 }
  70
  71 static unsigned int omap_getspeed(unsigned int cpu)
  72 {
  73         unsigned long rate;
  74
  75         if (cpu >= NR_CPUS)
  76                 return 0;
  77
  78         rate = clk_get_rate(mpu_clk) / 1000;
  79         return rate;
  80 }
  81
  82 static int omap_target(struct cpufreq_policy *policy,
  83                        unsigned int target_freq,
  84                        unsigned int relation)
  85 {
  86         int i, ret = 0;
  87         struct cpufreq_freqs freqs;
  88
  89         /* Ensure desired rate is within allowed range.  Some govenors
  90          * (ondemand) will just pass target_freq=0 to get the minimum. */
  91         if (target_freq < policy->min)
  92                 target_freq = policy->min;
  93         if (target_freq > policy->max)
  94                 target_freq = policy->max;
  95
  96         freqs.old = omap_getspeed(policy->cpu);
  97         freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
  98         freqs.cpu = policy->cpu;
  99
 100         if (freqs.old == freqs.new)
 101                 return ret;
 102
 103         /* notifiers */
 104         for_each_cpu(i, policy->cpus) {
 105                 freqs.cpu = i;
 106                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 107         }
 108
 109 #ifdef CONFIG_CPU_FREQ_DEBUG
 110         pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new);
 111 #endif
 112
 113         ret = clk_set_rate(mpu_clk, freqs.new * 1000);
 114         freqs.new = omap_getspeed(policy->cpu);
 115
 116 #ifdef CONFIG_SMP
 117         /*
 118          * Note that loops_per_jiffy is not updated on SMP systems in
 119          * cpufreq driver. So, update the per-CPU loops_per_jiffy value
 120          * on frequency transition. We need to update all dependent CPUs.
 121          */
 122         for_each_cpu(i, policy->cpus) {
 123                 struct lpj_info *lpj = &per_cpu(lpj_ref, i);
 124                 if (!lpj->freq) {
 125                         lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy;
 126                         lpj->freq = freqs.old;
 127                 }
 128
 129                 per_cpu(cpu_data, i).loops_per_jiffy =
 130                         cpufreq_scale(lpj->ref, lpj->freq, freqs.new);
 131         }
 132
 133         /* And don't forget to adjust the global one */
 134         if (!global_lpj_ref.freq) {
 135                 global_lpj_ref.ref = loops_per_jiffy;
 136                 global_lpj_ref.freq = freqs.old;
 137         }
 138         loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq,
 139                                         freqs.new);
 140 #endif
 141
 142         /* notifiers */
 143         for_each_cpu(i, policy->cpus) {
 144                 freqs.cpu = i;
 145                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 146         }
 147
 148         return ret;
 149 }
 150
 151 static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
 152 {
 153         int result = 0;
 154         struct device *mpu_dev;
 155
 156         if (cpu_is_omap24xx())
 157                 mpu_clk = clk_get(NULL, "virt_prcm_set");
 158         else if (cpu_is_omap34xx())
 159                 mpu_clk = clk_get(NULL, "dpll1_ck");
 160         else if (cpu_is_omap44xx())
 161                 mpu_clk = clk_get(NULL, "dpll_mpu_ck");
 162
 163         if (IS_ERR(mpu_clk))
 164                 return PTR_ERR(mpu_clk);
 165
 166         if (policy->cpu >= NR_CPUS)
 167                 return -EINVAL;
 168
 169         policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
 170         mpu_dev = omap2_get_mpuss_device();
 171
 172         if (!mpu_dev) {
 173                 pr_warning("%s: unable to get the mpu device\n", __func__);
 174                 return -EINVAL;
 175         }
 176         opp_init_cpufreq_table(mpu_dev, &freq_table);
 177
 178         if (freq_table) {
 179                 result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
 180                 if (!result)
 181                         cpufreq_frequency_table_get_attr(freq_table,
 182                                                         policy->cpu);
 183         } else {
 184                 policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
 185                 policy->cpuinfo.max_freq = clk_round_rate(mpu_clk,
 186                                                         VERY_HI_RATE) / 1000;
 187         }
 188
 189         policy->min = policy->cpuinfo.min_freq;
 190         policy->max = policy->cpuinfo.max_freq;
 191         policy->cur = omap_getspeed(policy->cpu);
 192
 193         /*
 194          * On OMAP SMP configuartion, both processors share the voltage
 195          * and clock. So both CPUs needs to be scaled together and hence
 196          * needs software co-ordination. Use cpufreq affected_cpus
 197          * interface to handle this scenario. Additional is_smp() check
 198          * is to keep SMP_ON_UP build working.
 199          */
 200         if (is_smp()) {
 201                 policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
 202                 cpumask_setall(policy->cpus);
 203         }
 204
 205         /* FIXME: what's the actual transition time? */
 206         policy->cpuinfo.transition_latency = 300 * 1000;
 207
 208         return 0;
 209 }
 210
 211 static int omap_cpu_exit(struct cpufreq_policy *policy)
 212 {
 213         clk_exit_cpufreq_table(&freq_table);
 214         clk_put(mpu_clk);
 215         return 0;
 216 }
 217
 218 static struct freq_attr *omap_cpufreq_attr[] = {
 219         &cpufreq_freq_attr_scaling_available_freqs,
 220         NULL,
 221 };
 222
 223 static struct cpufreq_driver omap_driver = {
 224         .flags          = CPUFREQ_STICKY,
 225         .verify         = omap_verify_speed,
 226         .target         = omap_target,
 227         .get            = omap_getspeed,
 228         .init           = omap_cpu_init,
 229         .exit           = omap_cpu_exit,
 230         .name           = "omap",
 231         .attr           = omap_cpufreq_attr,
 232 };
 233
 234 static int __init omap_cpufreq_init(void)
 235 {
 236         return cpufreq_register_driver(&omap_driver);
 237 }
 238
 239 static void __exit omap_cpufreq_exit(void)
 240 {
 241         cpufreq_unregister_driver(&omap_driver);
 242 }
 243
 244 MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
 245 MODULE_LICENSE("GPL");
 246 module_init(omap_cpufreq_init);
 247 module_exit(omap_cpufreq_exit);